In providing power to customers, electrical power utility companies employ a power grid distribution network that includes distribution-line-conductors (which are often referred to as power lines). Typically, difficulties or faults within the distribution network are identified only after occurrences of “events.” These events may merely result in a temporary loss of power for a limited number of customers, but more significant problems may occur.
Protection components and systems are known. “Reactive” components are particularly common. A reactive component is a device or system that is activated or deactivated by a fault event or its consequences. For example, a circuit breaker will open a distribution line as a response to excessive current, thereby protecting power distribution equipment. More sophisticated systems are also available.
Clearly, there are benefits to identifying conditions that precede fault events. For example, if it can be determined that a power line from a power transformer is experiencing intermittent fluctuations, scheduling a replacement of the transformer to avoid an outage event would be beneficial to the utility provider and its customers. Thus, “predictive” components and systems are desirable. Line monitoring devices and systems that monitor power parameters of equipment and power lines can provide useful information for the prevention and identification of power distribution faults or events.
Electrical arcs can occur in power distribution grids due to a breakdown of insulation on the conductors, typically at insulators or across open switch contacts mounted on utility poles where the installation strength is weakest and most easily overcome by an overvoltage event. Electrical arcs may be overvoltage effects from direct or nearby lightning strikes, coupled with insulator damage and/or pollution. Traveling arcs typically occur between either two or three high voltage electrical conductors. Arcs typically travel, or ‘motor’, away from the generator or source, driven by the Lorentz Force. The speed of a traveling arc is proportional to the arc current, which in-turn is dependent on available fault current at the site of the arc. Thus, the speed of an arc is proportional to the distance of the arc location to the substation. Arcs are driven by magnetic forces, so a change in the magnetic circuit can result in a change in arc speed. A traveling arc is a column of ionized gas (plasma) that provides a conductive path for fault current to flow between conductors. This arc plasma is destructive because of a) its ionizing capabilities and b) high temperatures developed in the gas, approaching 10,000° K.
Monitoring devices deployed in production environments can cause damage to the surface of the conductor under traveling arc conditions. When a traveling arc moves along a conductor, it will linger on any metal structure on or near the conductor. Thus, monitoring devices deployed on power distribution networks give traveling arcs a place to “hang out” or linger, and act as a physical barrier for the hot arc gases. This allows the traveling arc to damage both the conductor itself, and also the monitoring devices, which can cause power outages and expensive damage to the power distribution network.